Platform IO + Arduino UNO : hw debug vs software emulation

[MantaRayDeeJay]

Hi Everyone

I'm a newbie with VS Code + Platform IO.
In a first time, I'm trying to use the debug function with an Arduino Uno classic board.

I didn't well understand how to use the debug feature.
I have used to use a software debug (as a simulator without any physical board linked to the computer)
So I would like first use this debug working method.

But it seems, there is an issue, I have the following error message :

In English language, it would be :

PlatformIO: Initializing remote target...
.pioinit:13: Error in sourced command file:
:3333: The system tried to join a drive to a directory on a joined drive.

I don't know what is means.

Rem. 1 : The project can be build with "success" and I can upload the code into the board.
Rem. 2 : I have tried with a different folder location without any success.

[wassfila]

@MantaRayDeeJay

• just as a quick check, I had issues with platofrm io when I run projects from D: drive, I know it sounds stupid but I had some plugins that did not work well, as a quick check, try from a project on C: if you have the same issue, in the meanwhile, I might have to reproduce it, I'll check if I can use any other Arduino board should be similar.
• I could not find any arduino AVR board, I'll have to dig on my old stuff maybe I find one, otherwise I'll try with a different uC and Arduino
• In general, what I do for example in nRF52 I never use VS-Code to debug, I rather only rely on official debugging tools. I use a Segger debugger
  https://www.segger.com/products/debug-probes/j-link/models/j-link-edu/
  Apparently they have a studio for Atmel
  https://www.segger.com/products/debug-probes/j-link/technology/ides/atmel-studio/
• actually which debugger did you use ? I'm not familiar with the Atmel AVR HW board if it has an integrated debugger, can you post a link of steps you followed for debug, e.g. here an example
  https://hackaday.io/project/162302/instructions

[MantaRayDeeJay]

@wassfila
Moving the project folder from D:\ to C:\ doesn't solve the issue.
Rem. : Also tested with no space char in the full path.

For information, my setup :

• VS Code :
  Version: 1.65.2 (user setup)
  Commit: c722ca6c7eed3d7987c0d5c3df5c45f6b15e77d1
  Date: 2022-03-10T14:33:55.248Z
  Electron: 13.5.2
  Chromium: 91.0.4472.164
  Node.js: 14.16.0
  V8: 9.1.269.39-electron.0
  OS: Windows_NT x64 10.0.19043
• Platform io version :
  Core 5.2.5 - Home 3.4.1
• OS : Microsoft Windows [version 10.0.19043.1586]

[wassfila]

ok, unlucky guess, that is discarded

[MantaRayDeeJay]

@wassfila

• Currently, I don't have any hardware JTAG debug interface.
• About Segger, I think it should be great tools. The drawback : it is not lowcost products for Makers (Except maybe the EDU Mini version)
• I have ordered today the ESP-PROG for a later usage with espressif chips.
  Official Website info : https://docs.platformio.org/en/latest/plus/debug-tools/esp-prog.html
  YT "Swiss Accent Guy" Video : Free Inline Debugging for ESP32 and Arduino Sketches -> https://www.youtube.com/watch?v=psMqilqlrRQ

[wassfila]

yeah, the I have that one for the esp prog, I tried it. The segger edu mini is only around 16€. But it does not support esp, if that is your uC of choice.

[MantaRayDeeJay]

@wassfila

I just want to use the "debug" process in software mode (without any JTAG Hardware interface)
My steps :

• Open VSCode and load the project folder.
• Compile the code.
• Add a break point
• Click on the "Run & Debug" icon (CTRL+SHIFT+D)
• Select "PIO Debug (without uploading)" (3rd Option)
• Start Debugging (F5)

Rem. : I didn't modify the platformio.ini file :

[env:uno]
platform = atmelavr
board = uno
framework = arduino

[MantaRayDeeJay]

[wassfila]

@MantaRayDeeJay Do you have a reference or a guide that you followed ? if you can post the links, as I don't have an arduino uno right now, I can check the guides to see if they have any tricks, I'll also try with other Arduino boards, usually for hardware debug there has to be a debug_tool option on the config file, see
https://docs.platformio.org/en/latest/projectconf/section_env_debug.html#projectconf-debug-tool
see also
https://medium.com/@manuel.bl/arduino-in-circuit-debugging-with-platformio-9f699da57ddc

but now I realised you want to debug in software, does that mean without any board attached at all as with a simulator ? if that is possible, then I should be able to reproduce it.

[MantaRayDeeJay]

@MantaRayDeeJay Do you have a reference or a guide that you followed ? if you can post the links, as I don't have an arduino uno right now, I can check the guides to see if they have any tricks, I'll also try with other Arduino boards, usually for hardware debug there has to be a debug_tool option on the config file, see https://docs.platformio.org/en/latest/projectconf/section_env_debug.html#projectconf-debug-tool see also https://medium.com/@manuel.bl/arduino-in-circuit-debugging-with-platformio-9f699da57ddc

but now I realised you want to debug in software, does that mean without any board attached at all as with a simulator ? if that is possible, then I should be able to reproduce it.

• I didn't find any tutorial to use the Platformio debug feature with an Arduino Uno board.
• It seems, there is no JTAG feature with ATMEGA328 chips.
• So yes, I would like to use the platformio "debug" feature in "simulator" mode with the Arduino Uno board. (As per example with Microchip MPLAB IDE) But I don't know if it is possible, it seems not specified in the website documentation.

[wassfila]

I think what you need is a special case, neither hw nor sw, I'll explain below where you talk about SIMVAR

[MantaRayDeeJay]

@wassfila
About the the Segger J-Link EDU mini device, do you have some links where we can buy it ?
It seems sold out from most distributors. https://octopart.com/search?q=segger+edu+mini&currency=USD&specs=0

[wassfila]

I got it from Mouser long ago, when I search I get to this page
https://eu.mouser.com/new/segger/segger-j-link-edu-mini-debug-probes/
But then when I click on details, it is not found and by segger themselves it is out of stock. anyway, I would not recommend to get the Segger before you know which Target you'll run it onto, the ESP32 is not supported, I think Espressif need to produce cheap uC so they probably save cost on good debug features and toolchain, I did not had a good experience with the ESP-Prog, just the fact that they rely on OpenOCD shows that they only have it as optional feature not well supported, and I can tell you it's not easy to configure when it works at all after reading lots of different forums and youtube videos, not like the Segger tools that work 'out of the box' and 'always' without any headache.

[MantaRayDeeJay]

It seems I have partially found the solution :

To simulate an AVR device, we need an external tool as SIMAVR to simulate as example an ATMEGA328 chip with platformio.
https://docs.platformio.org/en/latest/plus/debug-tools/simavr.html

To do it, just add the following line in the platformio.ini file :
debug_tool = simavr

UPDATED on 2022-03-28 :
by default, the avr-stub debug tool is used.
https://docs.platformio.org/en/latest/boards/atmelavr/uno.html](url)

[wassfila]

indeed, debug can run on either of :

• A real target, with debug interface to stop the core and check its real registers
• A pure software emulator, this is running completely on PC and is a form of virtual machine
• A HW usually big and very powerful that can emulate a target architecture, in which case you connect to it like onto another HW

the docs.platoformio link you posted did not resolve but I searched with keywords "simvar AVR simulator", to be honest it does not look like an easy solution. Emulating hardware can be much harder than debugging a real HW, it is a fall back sometimes for projects that needs to start developping sw before the real chip is even available.

[MantaRayDeeJay]

@wassfila
After doing some test and researches, it seems that's very strange.

By default, without specifying a debug tool, the debug tool used by default is avr-stub.
https://docs.platformio.org/en/latest/boards/atmelavr/uno.html

By switching from one to other debug tool, the behavior and issues are different.
By using the simavr debug tool, I can run the debugger but I meet other issues with breakpoint usage.
I have also noticed that error messages or issue behavior are different after trying again to restart the debugging.

I have posted an new thread directly on the platformio forum (explain the test sequence with the 2 debug tools) :
https://community.platformio.org/t/platformio-debbuging-with-arduino-uno-blink-template/26841

[wassfila]

Yeah pio community seems like a good spot. If it is simulation, I can try it, I just cannot test on real HW, who does not have an Arduino UNO lol

for some reason github is changing the url of the links you post, when I copy paste them in the browser they work
here I posted the same you did just to check if it works
https://community.platformio.org/t/platformio-debbuging-with-arduino-uno-blink-template/26841

[MantaRayDeeJay]

1. Yes, you can try to test it by simulation, thanks
2. The forum thread link works well !

[wassfila]

@MantaRayDeeJay
Also if you post a link to the project you're trying in pure sw mode, I can test it.

[MantaRayDeeJay]

PIO Home -> Project Examples -> arduino-blink (1st on top in the list)

[wassfila]

Without having anything connected I have an error that looks like yours, so maybe your serial port connection is wrong or you did not flash the program before you start debugging ?

I have to check more in depth now what they automatically put on the debug config PIO Debug (without uploading)

[wassfila]

so this is not a pure emulator after all, this is a sw debug that runs on the Core itself but it needs areal board and a serial port
debug_tool = avr-stub
https://docs.platformio.org/en/latest/plus/debug-tools/avr-stub.html#configuration
so cannot test it unfortunately

[MantaRayDeeJay]

Yes, it is not clear for me. I'm asking if we can use only the platformio debugger in a "Software Simulator Mode".

The Original Arduino Uno R3 board (20€)
https://store.arduino.cc/products/arduino-uno-rev3

We can find some clone models on asian market for about 10-15€

[wassfila]

@MantaRayDeeJay I don't think there is an Arduino simulator in platformIO, at least I've never seen an Arduino simulator altogether. As you also seen on many video, I've only seen different ways to debug Arduino that need a real HW.
The reason why there are not many simulators for uC is that a simulator only simulate the core, then what do you do with the peripheral.
I've worked in the past (loooong time ago) With "Isis" which was not only a Pic uC simulator, but you could also attach electronic components to the pios and make a full electronic simulation while debugging the core step by step. I have not seen any equivalent uC environment since then.
VSCode is only a text editor with very powerful plugins system, but all the logic, comes from the plugins. E.g. platformio can run from command line.
Now even platformio is nothing but a project management system, that wraps tools coming from vendors, Arduino is similar, it is a project management compiling c++ for for atmel, then got support from other hw.
In other words, if you want to discover the toolchain capabilities, go to the hw vendors websites directly, not to the middelware 3rd parties, as they onoy wrap the vendors tools. Go toAtmel, Nordic, ST, Nxp,... For debug you can also go to Debuggers companies, e.g. Segger, Lauterbach, Arm,... as even the hw vendors delegate the debug toolchain to them.
Simulation is not much of a fashion, if you really need it, it is going to be hard and not something to start with, but you can go direction qemu emulation, or mabe electronic simulation tools to see if they integrate uC emulation as well, I doubt something free exist but I'd have to make a new survey.

[MantaRayDeeJay]

@wassfila
I have seen this great video "Is Visual Micro the better Arduino IDE? Including ESP32 inline debugger"
https://www.youtube.com/watch?v=7SiprW-goj0
It explain the 2 differences modes between Serial Debug and Hardware (Jtag) debug mode. (@11mn28s)

I have also seen this video "Arduino Uno GDB Debugging"
https://www.youtube.com/watch?v=s-EB0ykiUi8

In all cases, the board seems to be needed for debugging.

[MantaRayDeeJay]

Lot of good links here :

• Debugging Explained for Arduino : https://www.visualmicro.com/page/User-Guide.aspx?doc=Debugging-Explained.html

• Debugging your Arduino Sketch Visual Micro : https://www.visualmicro.com/page/User-Guide.aspx?doc=Debugging.html

• Differences between Visual Micro debugging and "classic" debuggers : https://www.visualmicro.com/page/User-Guide.aspx?doc=Debugging-Differences.html

• Gdb Debugging: Comparison of Debugging Systems : https://www.visualmicro.com/page/User-Guide.aspx?doc=Arduino-gdb-Differences.html